Be sure that your CPU fan is plugged into the correct header (as usual, my Athlon XP rig will not turn on at all if the fan is plugged into FAN2 instead of FAN1) - plus my mobo has special LED's to check if an effective amount of power is flowing through - usually if none of the above work, your PSU has blown it. About getting a new power supply, get a QUALITY one (e.g. Antec, Enermax, etc.) - a 350W quality PSU will have a longer shelf life than a low-quality 430W.